Low temperature hybrid plasma-catalytic methanation over Ni-Ce-Zr hydrotalcite-derived catalysts

•Hydrotalcite-derived catalysts promoted with Ce and Zr•Hybrid plasma-catalytic process•80% CO2 conversion and complete selectivity to CH4 at 110 °C, adiabatic conditions•Reaction controlled by the presence of zero-valent Ni of medium crystal size•No clear influence of basicity

The activity of Ceria and Zirconia-promoted Ni-containing hydrotalcite-derived catalysts was assayed in a hybrid plasma-catalytic process for the hydrogenation of carbon dioxide into methane at low temperatures and in the presence of a cold dielectric barrier discharge (DBD) plasma. High methane yields, around 80%, were measured under hybrid plasma-catalytic conditions, even at very low temperatures (110 °C, adiabatic conditions). In the absence of plasma, acceptably high CO2 conversions and methane yields were only observed at temperatures higher than 330 °C. The presence of completely reduced Ni-crystallites of intermediate size, more readily available on the non-promoted catalysts was found to enhance the methanation reaction. Ce and Zr addition did not result in a noticeable improvement of the catalytic activity.

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